Basically, silver halide color photographic materials are processed by means of a color development process and a desilvering process. Thus, the exposed silver halide is reduced with a color developing agent to produce silver in the color developing process and the oxidized color developing agent reacts with a color forming agent (coupler) to provide a dye image. The silver which is formed at this time is then oxidized by means of a bleaching agent, converted into a soluble silver complex by the action of a fixing agent, and dissolved out and removed in the desilvering process.
In recent years, strong demands have arisen in the industry for more rapid processing. Specifically, it is important to shorten the time required for processing, and, in particular, to shorten the desilvering process which accounts for about half of the processing time.
Bleach-fix baths in which an amino polycarboxylic acid Fe(III) complex and a thiosulfate are contained in the same bath as disclosed in the specification of German Patent 866,605 were known in the past as a means of speeding up the desilvering process. However, originally, amino polycarboxylic acid Fe(III) complex salts which had a weak oxidizing power (bleach power) and thiosulfates which had a reducing power were present together. Thus, the bleaching power was remarkably weak and it was very difficult to desilver adequately high speed, high silver content camera photosensitive materials and, therefore, these baths could not be used in practice.
On the other hand, methods in which various bleaching accelerators are added to the bleach bath, bleach-fix bath of the bleach or bleach fix prebaths have been suggested as methods of increasing bleaching power. Bleaching accelerators of this type include various mercapto compounds such as those disclosed in U.S. Pat. No. 3,893,858, British Patent 1,138,842 and JP-A-53-141623 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application"), compounds which have disulfide bonds such as those disclosed in JP-A-53-95630, thiazolidine derivatives such as those disclosed in JP-B-53-9854 (the term "JP-B" as used herein refers to an "examined Japanese patent publication"), isothiourea derivatives such as those disclosed in JP-A-53-94927, thiourea derivatives such as those disclosed in JP-B-45-8506 and JP-B-49-26586, thioamido compounds such as those disclosed in JP-A-49-42349, dithiocarbamates such as those disclosed in JP-A-55-26506, and arylenediamine compounds such as those disclosed in U.S. Pat. No. 4,552,834.
Furthermore, methods in which processing is carried out with mercapto compounds or precursors thereof from among the aforementioned bleach accelerators present in the photosensitive material are also known. However, in cases where the mercapto compounds are included in the photosensitive material, the compounds may have a pronounced effect on the photographic properties. Further, sparingly soluble salts may be formed from the mercapto compounds and the silver halide in the undeveloped parts of the photosensitive material. Thus, there are many problems associated with these methods.
On the other hand, disclosures concerning bleach accelerator releasing couplers have been made in Research Disclosure, Items Nos. 24241 and 11449, and in the specification of JP-A-61-201247 (corresponding to EP-A-193389). These documents disclose that the bleaching rate is increased when a bleach accelerator releasing coupler is used.
However, the increase in the bleaching rate is limited, even when the above-mentioned bleach accelerator releasing couplers are used, and thus, a satisfactory level has not been reached in practice. Furthermore, if the bleaching time is shortened by adding larger amounts there are clear side effects, such as loss of speed, due to the leaving groups.